Ahh, frog moss can be awful. If the hot bath doesn't work, some people suggest giving the frog some kind of oil but I've never been able to find anything saying whether that would be toxic to them or not. Hate to say it, but if he doesn't poop in a while a vet visit might be the only thing left to do (unless someone else wants to chime in with something I've never heard of?). Impaction (severe constipation) can eventually kill frogs.

Your care looks pretty good, all I can see is that it might be a bit cold at night.